1. Field of the Invention
This invention relates to improvements in image capture and display devices. More particularly, this invention pertains to solid state arrays used for light imaging and displaying of documents.
2. Description of the Related Art
Three separate devices are required (a) to accept hand-drawings, (b) to acquire graphic information from a document, and (c) to display images. A typical contact-type document scanner uses a linear scanner that requires mechanical motions and an illumination source, which reduces the advantage of compactness. There are several techniques for inputting hand drawings, such as capacitive or optical position sensors, but these are not capable of also accepting an image from a document.
Current color flat bed scanners work in one of two modes. The first mode is to mechanically line scan an image in three colors. The second mode is to view the document with a CCD camera in three colors. Both of these systems operate with perfect color registration using filtered illumination; but often the perfect registration is abandoned because of its slowness. A mechanical line scanner can be particularly slow when three color passes are used (HP IMAGEPROc). A one pass system uses three rows of line sensors with color separation filters, and a white illuminate. Registration is still not perfect, and more importantly, the scan speed for one page is still limited to several seconds for a mechanical scan platform.
Addressable two-dimensional image sensor arrays made from amorphous silicon were conceived by M. Matsumura et al (IEEE Electron Device Letters, vol. EDL-1, page 182, 1980) and were demonstrated by Street et al (Material Research Society Symposium Proceedings, vol. 192, page 441, 1990). The use of these arrays for contact imaging was reported by Powell et al (Material Research Society Symposium Proceedings, vol. 258, page 1127, 1992).
Street et al (Material Research Society Symposium Proceedings, vol. 192, page 441, 1990) describe the use of large area amorphous silicon arrays together with a suitable phosphor for x-ray imaging. Present x-ray detectors result in an image on film or on a cathode ray tube display. In either case, the image cannot easily be viewed where it is formed.